In "Amazon Women in the Mood", Kif is trying to talk to Amy but is too nervous. Zapp realizes that Amy knows Leela, whom he is constantly trying to seduce. Zapp contacts Leela and sets up half a double-date. Kif gets some bad advice from Zapp which causes Leela to proclaim the date over.
After a brief trip to the bathroom to fix their makeup, they begin storming out but are stopped by Kif's emotional karaoke performance. Soon after, the men and women land on Amazonia and are to be killed by snu-snu. After finding out the truth, Amy saves Kif, he asks her what she'd like to do, and she whispers something in his ear. His response is a flustered, incomprehensible mumbling.

In "Where the Buggalo Roam", Kif tries to impress Amy and her parents, but Amy's parents don't think that Kif is a good boyfriend, though they were the one who introduced him to her. In the end, Amy and Kif "make love for the second time!"

In The Beast with a Billion Backs, their relationship is taken to another level as Kif asks Amy to be his Fonfon Ru, an equivalant to marriage of his race. At the Fonfon Ru ceremony, which is held on Amphibios 9, Kif's home planet, she and her parents are introduced to Kif's parents and the ceremony concludes succesfully, with Amy later calling Kif her "husband" although no such term was used in the Fonfon Ru ceremony. Later on, Kif is squashed to death during an attempt to shoot a missile at another universe, causing Amy to attend his funeral ceremony on his home planet. With Kif deceased, Amy has a short affair with Zapp Brannigan during the crisis Yivo's tentacles initiate. After Yivo reveals shklerself, shklee resurrects Kif, but he feels unable to continue his relationship, or for that matter, marriage with Amy after hearing of her promiscuity.

In the end of Into the Wild Green Yonder, Kif and Amy seem to get back together as they go into the wormhole. They later temporarily split up at the beginning of "Proposition Infinity", only to get back together at the end of the episode.

In the previous two universes (and possibly the current third one) by 3050 Amy and Kif's relationship has apparently ended somehow as Amy started dating Cubert.